I was wondering how long after a question is asked does one constrict the anal spinter or bite the lip in order for the CM to work?
3 to 5 seconds
My advice: Use the countermeasures right up to the point where the polygrapher straps you into the chair. At that point, don't screw with your own head.
And the so-called "anal pucker": Save that for your next enema or proctology exam. I've seen what it looks like on a polygraph. If you don't want to look like a dumb anal sphincter, don't let your anal sphincter make you look like one.